POWER SUPPLY ADVICE-OPINIONS WANTED!!

[MrHorsepower]

Hi guys, it's been a while since I posted. I was called out of the country for work and I'm just getting back to my Boss5 conversion. To catch everybody up. I've got a Boss5 that I am re-assembling after a fairly complete refurb, every nut, bolt, bearing got some love. I also gave the old girl a paint job.

I will be switching to MACH with the stock steppers, Gecko 203V's a CUBLOC 280 for IO via MODBUS. I already have an NCPOD but I think I will switch to a SmoothStepper since the POD doesn't get any support or developement. I've got a really nice 15" touch screen for a new flash screenset. I've also got a KEB VFD that I plan to use to control my spindle motor.

Since I'm using the VFD I don't have a need for 3ph power for the motor. I seems wrong to run my phase converter just to power the stock 3ph transformer for the DC power to the steppers. I'f I scrap (DON'T WORRY I WON'T JUST THROW IT AWAY--LOL) the stock transformer. What is the lowest voltage I will get decent power with; with these NEMA 42's?

They were running at 60V in the stock setup, but I cant find out enough info about them. I was thinking of buying 3 of these

http://cgi.ebay.com/48V-DC-7-3A-350-...item5ad21289ff if this link doesn't work they are 48VDC 7.3A 350.4watt regulated supplies.

Since the 203's will chop the current to 7A they should work, right??

This might not be the right board but I sure would appreciate some advice, I serched but couldn't come up with the answers. Thanks in advance.

[MrHorsepower]

HELLOOOOOOO??????

[jalessi]

MrHorsepower,

Why not use the stock transformer?

I would not waste any money on new power supplies.

A new rectifier and filter capacitor would be my route.

Jeff...

[MrHorsepower]

The stocker is a 3ph unit. I don't need to run 3ph power to my spindle any more because of the VFD I'm using. I don't want to run my phase converter just to power a transformer. After implementing the VFD I won't have any other 3ph equipt. in my shop. My Lathe and othe mill (welders, saws, drill, beltsander, etc...) are all single phase. It doesn't sound right to run the rotophase just to get DC power.

[Al_The_Man]

Is the secondary supply for the steppers 3 phase rectifier, or is it a single phase winding?
Al.

[jalessi]

MrHorsepower,

I did not know the stepper transformer was three phase input, sorry for giving you bad advise.

Checkout Antek, they have some larger power supplies as well as transformers.

http://www.antekinc.com/index.php

Jeff...

[Al_The_Man]

Do you have a print of the input power supply section?
There is an indication out there that you may be able to use the existing set up.
A 3 phase transformer is just 3 separate primaries, sometimes a single secondary is used, it is possible on occasion to use one section.
Al.

[MrHorsepower]

I thought about just using it that way, but on single ph I would only be able to use one section. It is a 3ph secondary as well. From there it went to 3 rectifiers and 2 pair ea. caps. If I use just one section for all the motors it's just gonna fry. I've put a lot of love into this thing and don't mind spending another couple of hundred on DC power. My question is really do I dare try to run these Nema42's on 36V? 24V? I don't do much heavy cutting at all. Is the a benifit one way or another as far as resonance?? Hey Marris???

[Al_The_Man]

Originally Posted by MrHorsepower I thought about just using it that way, but on single ph I would only be able to use one section. It is a 3ph secondary as well. From there it went to 3 rectifiers and 2 pair ea. caps. If I use just one section for all the motors it's just gonna fry.

Not necessarily, it sounds like each section has its own 1 phase secondary, if the transformer has delta primary, most likely, then parallel them (primaries) up across 240v 1 phase.
Transformers are pretty rugged devices and it will warn you well ahead of time if it does not like it.
Al.

[MrHorsepower]

Can I do that?? Also since your answering...LOL Should I just bridge all of the DC together to a common post after the Cap.'s? I would like to be able to pull power from the "pool" for a 4th axis insted of cheating one axis. I attached a pic of the transformer spec. plate. Take a look. I think I know what you are saying about how to wire this, but I thought I had ruled that out years ago when I started this project. Still trying to re-wrap my mind around the electricals. Thanks for all the help!!!!!!!!

[Al_The_Man]

It is a long time since I did it, but IIRC you just treat the three primaries as three separate transformers and connect in parallel.
If it works and the outputs are identical then you could parallel the DC up.
Try it a step at a time and off load with a suitable fuse or breaker.
The primary current will be higher due to not spread over 3 ph.
Al.

[jalessi]

MrHorsepower,

I have a very similar transformer on my Hurco and it runs fine on single phase 220.

Jeff...